The present invention relates to a method for starting a direct-injection internal combustion engine of a vehicle, making it possible to accelerate the starting phase by adapting the quantity of fuel injected during said starting phase, before the engine reaches it steady operating speed, by means of an injection system containing a high-pressure fuel injection pump.
The quantity of fuel to be injected during the starting phase of such an engine is dependent on the temperature of the engine, on the number of top dead centers passed by the crankshaft before the engine reaches it steady operating speed, on the speed of the engine during said starting phase, and likewise on the quality and on the type of fuel used, present in the gasoline tank, which may have been identified or noted in the course of driving the vehicle on a previous occasion.
During starting following filling of the fuel tank with a fuel, of which the characterizing features have changed in relation to the fuel contained before said filling, the lack of accuracy in the quantity of fuel to be injected during starting may give rise to longer starting times or even failures to start.
Document DE102011077404, which proposes a method for identifying the type of fuel before starting the engine, in order to adapt the dosage of the injected quantities of fuel accordingly ahead of the injection, is already familiar. A suchlike method offers the advantage of optimizing the performance of the engine and preventing the injection of an inappropriate fuel into the engine as the result of a fueling error, for example. The method according to this document consists of comparing the curve for the build-up in pressure in the rail as a function of time (dP/dt) with the curves recorded in the ECU (“Engine Control Unit” in English), and thus determining the type or the quality of fuel present in the rail ahead of the injection. The method uses the determination of the Young modulus of the fuel. The quantity of fuel injected may thus be adjusted depending on the type or on the quality of fuel detected. An advantage of said method is that it permits the determination of the type of fuel before combustion, and thus improves the combustion efficiency.